1. Field of Invention
The present invention relates to housings for reverse osmosis filter cartridges and methods for manufacturing the same.
2. Description of Related Art
Reverse osmosis filtration is well known. A solution comprising a solvent and at least one solute is directed toward a semi-permeable membrane at a pressure that is greater than an osmotic pressure. This causes the solvent in the solution, but not the solute, to permeate through the semi-permeable membrane, leaving behind a concentrate.
Conventional reverse osmosis filtration assemblies (e.g., for use in filtering water) include a reverse osmosis filter cartridge, which is contained within a housing. Reverse osmosis filter cartridges for use in such applications typically comprise an elongate, cylindrical, spirally wound semi-permeable membrane. In the case of water filtration, an aqueous solution (e.g., sea water) is directed toward the outer wall of the cylindrical semipermeable membrane. Water permeates through the semipermeable membrane and find its way to an inner flow chamber, which is in fluid communication with a permeate output port. The partially de-watered residual portion of the solution that does not pass through the semipermeable membrane to the inner flow chamber is referred to as a concentrate, and is typically discharged from the housing through either a concentrate output port formed in an end cap that retains the reverse osmosis filter cartridge within the housing or through a side port formed in the housing.
The housing containing the reverse osmosis filter cartridge must be capable of withstanding the substantial internal pressures necessary to force solvent from the solution through the semipermeable membrane. Conventionally, such housings have been formed of steel, which is both expensive and heavy, or of composite glass fiber-reinforced plastics. One example of the latter type of housing is disclosed in Hlebovy, U.S. Pat. No. 5,866,001.
The reverse osmosis filter cartridge housing disclosed in Hlebovy is likely lighter in weight than a conventional steel reverse osmosis filter cartridge housing, but it suffers from other drawbacks such as manufacturing complexity and difficulties in readily customizing the product for a variety of different end use applications.